567. AGERATINA LIGUSTRINA

Compositae

Nicholas Hind

Summary . Ageratina ligustrina is illustrated in colour. Its history, cultivation

and distribution are discussed and accompanied by a black and white plate of

dissections.

With a highly scented, winter fl owering, easily grown shrub de-

scribed variously as ‘ elegant ’ , ‘ everybody ’ s plant ’ , ‘ useful ’ and with

the ‘ strongest recommendation ’ one may wonder what we have all

been missing. Such have been the descriptions of the subject of

this plate, Ageratina ligustrina (DC.) R. M. King & H. Rob., off and

on since the middle of the nineteenth century, one might ask why

aren ’ t we all growing it. The species was considered good enough

to have been awarded an Award of Garden Merit in 1996 ( Royal

Horticultural Society, 2004 ), and some 30 suppliers were listed in

the RHS Plant Finder 2006 – 07 ( Lord et al., 2006 ), and an equivalent

numbers have been listed over the last fi fteen or more years (cf.

Lord, 1990, 1996 ). It is even scented enough for Genders to have

mentioned it in his encyclopaedia ( Genders, 1978 ).

Hilliers ’ Manual ( Hillier, 1977 ) suggested that the species was in-

troduced into cultivation in 1867, although Bailey (1939) hinted

that it was probably in cultivation ‘ since about 1830 under a great

variety of names, but chiefl y as E. Weinmannianum . ’ There is ample

evidence ( Körnicke, 1858; Regel, 1867; Baker, 1869; Sheppard,

1875; Dalyrymple, 1876 ; Anon., 1876; Westland, 1877; Crane,

1879 ) that there has been a lot of interest in this plant, although

relatively little has been written about it recently. It has been listed

in most of the major compendia, dictionaries and encyclopaedias

(e.g. Bean, 1973; Hillier, 1977; Thomas, 1992; Royal Horticultural

Society, 1996; Galloway, 2000 ) and was listed in one recent specialist

popular book (e.g. Sutton, 2001 ). It was certainly in cultivation at

Kew in the late 1860s.

Ageratina ligustrina belongs to the tribe Eupatorieae which contains,

amongst many other well-known plants, Ageratum conyzoides L.,

Eupatorium cannabinum L. (HEMP AGRIMONY), and Stevia rebaudiana

(Bertoni) Bertoni, the source of a natural sweetner and sugar

substitute - stevioside. Belonging to the subtribe Oxylobinae

Ageratina ligustrina DEBORAH LAMBKIN

Plate 567

R. M. King & H. Rob., with some 265 species Ageratina is the larg-

est genus and possesses perhaps two species of note, the weedy

A. adenophora (Spreng.) R. M. King & H. Rob. and A. riparia (Regel)

R. M. King & H. Rob.; King & Robinson (1987) placed A. ligustrina

in subgenus Neogreenella R. M. King & H. Rob.

The synonymy of this taxon is extremely complicated, not least by

the range of horticultural names that appear to have been applied to

it. Vatke (1872) appears to have been the fi rst author to attempt some

listing, although he has been given little, or incorrect, credit in the

literature (c.f. Voss, 1894; King & Robinson, 1987 ). Vatke ’ s list provided

twelve synonyms, and these were repeated by Voss (1894); some of

them were credited solely to Voss by King & Robinson (1987) :

‘ Eupatorium biceps Klotsch – which appeared in herb. B, as mss. and in

hort.

E. myriadenium Schauer, Linnaea 20[sic! = 19]: 721 (1847).

b weinmannianum (Regel & Koern.) based on Eupatorium weinmannianum Regel

& Koern.

Eupatorium glabellum Otto, in herb. B and in hort.

Eupatorium glabrum hort.

Eupatorium glabratum hort.

Eupatorium glaucum Huegel in hort.

Ageratum glaucum hort.

Eupatorium album hort.

Ageratum album hort.

Eupatorium odoratum hort.

Eupatorium odoratissimum hort.

Eupatorium roseum hort.

Eupatorium morisii hort., non Vis.

Eupatorium iodopappum Sch.Bip. in herb. B, in horb. hort. bot. B. ’

The only differences noted by Voss was that Ageratum album was

cited ‘ hort. non Steud. ’ , and Eupatorium b weinmannianum was com-

bined as a forma.

Other names have also appeared in horticulture including:

Eupatorium fl oribundum hort. The whole are put into context in the fol-

lowing description.

C ULTIVATION . This species has a long history of cultivation be-

ginning just after it was fi rst described and brought into cultivation

in various nurseries and botanic gardens back in the early 1800s.

Although still mentioned in the horticultural literature it has ebbed

and fl owed in favour with enthusiastic accounts on its cultivation

in the late 1800s ( Sheppard, 1875; Dalyrymple, 1876 ). Although

the plant I am growing came from stock in RBG, Kew in 1989,

the Kew plant has long-since been dead so it is clearly not persistent.

It is grown in places as far apart as the National Botanic Gardens,

Glasnevin and gardens in South Australia.

General advice has often been to over-winter the plants in cool

greenhouses, even in southern Europe ( Galloway, 2000; Sutton,

2001 ). Categories of GI, or H3 have been recorded as hardiness

ratings, suggesting that the species is tender to temperatures below

5 ̊ C (41 ̊ F)(RHS 1996). I have found it hardy to -12 ̊ C, and there

are many reports supporting this hardiness throughout the UK, and

have successfully grown the plant in my garden in Reading since

fi rst propagated from a cutting back in 1989. Several winters have

seen hard frosts, both in my front and back gardens, where it really

doesn ’ t receive much in the way of protection. The only real dam-

age, strangely, was during a sharp -6ºC frost during December of

last year (2005) when all of the developing infl orescences were killed

off. However, several open infl orescences towards the base of the

plant were unaffected.

Whether in sheltered spots, or in the cool greenhouse, this plant

certainly offers late season colour and a heady sweet scent; when

fl owering during the summer it offers much more. It is an excel-

lent plant for attracting insect, especially if it fl owers in the spring,

summer and autumn. My own plants in high summer attracted

honey bees, humble bees, bumble bees, solitary bees, hover fl ies

and butterfl ies, and provided both pollen and nectar, as well as

producing a delightful sweet scent on the hottest days, competing

extremely well with a nearby juniper and Santolina . Late autumn

and winter fl owering can add a useful burst of white when little

else is fl owering, and it seems little affected by all but the hardest

frosts. Hard frosts may affect hard-pruned plants if pruned too

early with the young shoots just starting to grow. I have both

hard-pruned plants in my garden in Reading, as well as let them

go. Early pruning, before any new growth is evident usually results

in plants fl owering the same year at about one metre tall; plants

left un-pruned can carry on fl owering and growing, often reaching

two metres tall, and almost the same across, within two or three

years. The leaves will wilt in excessive drought conditions, but

generally the plant is excellent in most soils, except the most heavy.

It enjoys full sun, but can become leggy in partial shade, which

should be avoided.

P ESTS . I have never found any serious pest problems with the

plant and even the vine weevil, which is a serious pest in gardens

in the area, leaves it well alone.

P ROPAGATION . This species is perhaps easiest to propagate by

softwood cuttings. There is some difference of opinion as to the

best time to take cuttings. Sheat (1948) recommended taking fi rm

side shoots, with heels, between October and November and placing

in a cold frame in standard compost. I prefer softwood cuttings

taken as soon as frosts have past, or even in summer (June), and

the cuttings placed in a 50:50 mix of silver sand and sphagnum

peat (or its equivalent); pots can be placed in a propagator or simply

enclosed in a large plastic bag after a thorough misting. Rooting

usually takes place in a few weeks and when well rooted the plantlets

can be potted on, or planted out into their fi nal growing positions.

By preference I let the plants establish themselves in pots so that

they can compete with surrounding plants. Too much shade or

dominating plants can check growth of young plants. Potting on

should be into John Innes No. 3 with the addition of some sharp

grit. Pot grown plants should not be allowed to dry out in hot

weather as they tend to wilt quickly. Once established, border plants

are remarkably tolerant to drought in most years.

Mansfi eld (1945) suggested that the best method of propagation

is actually by seed, which is best sown in February at between 15º

and 20ºC. Ordinary seed compost is best, although I would prefer

the addition of sharp sand or grit.

C ULTIVARS . There is only one record that I have been able to

trace for cultivars of this species: ‘ SNOWDRIFT ’ [apparently a syn-

onym of ‘ SNOWFLAKE ’ ]. This was the name applied to a cultivar

which was submitted, and given, plant breeders rights in 1992, but

withdrawn in 1994. There are no subsequent records of this cultivar,

which was apparently a ‘ whiter ’ form, and there was no detailed

description made available.

Ageratina ligustrina (DC.) R. M. King & H. Rob., Phytologia 19(4): 223

(1973).

Eupatorium ligustrinum DC., Prodr. 5: 181 (1836). Type : ‘ in Mexico ad

Tamaulipas legit cl. Berlandier .[2143] … (v.s.) ’ . Lectotype (selected here):

G-DC – the specimen clearly labelled as above; isolectotypes : G-DC,

K, US. NB. The K isolectotype has two labels, one printed blue label

(Herbarium Berlandierianum Texano-Mexicanum ’ simply with a pencilled

number on it, the other white and penned with ‘ No 2143 = 726/fl . albi

alt. 4 – 6 p./Sarahuales de Jula a Sa Barbara/Nov, 1830 ’ . It is likely that

the other collection mounted on this sheet is a further duplicate, although

labelled ‘ 2140 ’ alongside of which B.L. Robinson has commented that

‘ This “ 2140 ” is clearly a clerical error for 2143. Berlandier ’ s 2140 was a

Dyssodia . ’ The US isolectotype has only ‘ de Tula á Tampica ’ on a hand

written label, but ‘ In Mexico ad Tampico de Tamaulipas ’ on a printed

mimeographed label – of which someone has made an appropriate com-

ment.

Eupatorium micranthum Less., Linnaea 5: 138 (1830), nom. illegit., non Lag.,

Gen. Sp. Pl. : 25 (1816) = Ageratum corymbosum Zucc.

? Eupatorium semialatum Benth., Pl. Hartw. : 76 (1841). Types : [ ‘ Sequuntur

plantae Guatemalenses (N. 523 ad 570), pleraeque circa Quezaltenango

mensibus Novembri et Decembri lectae, tum in temperatis montanis, quam

in caldis urbem inter et littus Oceani Pacifi ci, perpauceae jam mense Oc-

tobri collectae circa Comitan ad fi nes Mexicanorum. ’ ] ‘ – Sunil. – Etiam in

agro Mexicano legit. cl. Graham . ’ Lectotype (selected here): Hartweg 523

– K. (See notes in discussion as to selection of lectotype, as well as dubi-

ous synonymy.) Syntype : Graham (32) – K.

E. myriadenium Schauer, Linnaea 19(6): 721 (1847). Type : ‘ In Mexico, loco

non designato: Aschenb. [ orn ] n. 358. ’ Location of type not specifi ed but

probably B ( † , presumed destroyed during WWII): isotypes may exist in

few herbaria but none located.

Eupatorium weinmannianum Regel & Körn., Index Sem. Hort. Petrop. : 41 (1857).

Type: not cited; probable isotypes K x 2.

Eupatorium biceps Klotsch ex Vatke, Bot. Zeit. 30: 719 (1872), nom. nud. pro

syn.

Eupatorium popocatapetlense Schlchtdl. ex Hemsl., Biol. Cent.-Amer., Bot. 2: 99

(1881), nom. nud.

Eupatorium ligustrinum DC. f. weinmannianum (Regel & Körn.) Voss, Vilm. Blu-

mengaert., ed. 3, 1: 448 (1894).

Eupatorium glaucum Hort. ex Sieb. & Voss, Vilm. Blumengaert., ed. 3, 1: 448

(1894), nom. nud. pro syn.

Eupatorium erythropappum B. L.Rob., Proc. Boston Soc. Nat. Hist. 31: 248 (1904).

Type : ‘ Mexico: Alvares, San Luis Potosi, 28 September to 3 October,

1902, Dr. Edw. Palmer , no. 200. ’ Holotype : GH.

Eupatorium (§ Subimbricata) caeciliae B.L.Rob., Contr. Gray Herb. 90: 23 (1930).

Type: ‘ Guatemala: mountain woods between Totonicapam and Los En-

cuentros, Departments Qeuzaltenango and Sololá, 25 Sept. 1896, Caecilie

and Eduard Seler , no. 2361. ’ Holotype : GH.

Eupatorium plethadenium Standl. & Steyerm., Publ. Field Mus. Nat. Hist. Bot.

Ser. 23: 186 (1944). Type : ‘ Guatemala: Dept. Chimaltenango: In Cupressus

forest, region of Santa Elena, Cerro de Tecpám, alt. 2,400 – 2,700 meters,

December 26, 1938, Paul C. Standley 61100. ’ Holotype : F.

Eupatorium vetularum Standl. & Steyerm., Publ. Field Mus. Nat. Hist. Bot. Ser.

23: 190 (1944). Type : ‘ Guatemala: Dept. Totonicapán: Low damp thicket,

common, region of Chiu Jolóm, mountains above Totonicapán, on the

road to Desconsuelo, alt. 2,800 – 3,100 meters, January 23, 1941, Paul C.

Standley 84404. ’ Holotype : F.

Ageratina caeciliae (B.L. Rob.) R. M. King & H. Rob., Phytologia 19(4): 220

(1970).

Ageratina plethadenia (Standl. & Steyerm.) R. M. King & H. Rob., Phytologia

24(2): 95 (1972).

Eupatorium ligustrinum DC. var. villiferum B.L. Rob., Contr. Gray Herb. n.s. 75:

10 (1925) = Ageratina saltillensis (B.L. Rob.) R. M. King & H. Rob.

D ESCRIPTION . Evergreen perennial shrub, or sometimes subshrub , to 1.5 – 2.7 ( – 5)

m tall and 2 m ( – 5m) across. Stems mid-brown, well-branched and leafy in

upper portion of older stems, or almost throughout if fl owering growth pro-

duced that year from base. Leaves opposite, petiolate, petiole 6 – 20 mm long,

grooved above, lamina 25 – 100 ( – 150) mm long x 15 – 35 ( – 45) mm wide, base

acute to acuminate or sometimes with auriculate basal portion to lamina on

petiole, discolourous, mid-green and glossy above, lighter grey-green beneath,

with very sparse (sometimes denser) adpressed eglandular hairs above and

beneath, often moderately glandular-punctate, punctae sometimes amber-

coloured, midrib prominent beneath and primary venation translucent green

and scarcely prominent beneath, midrib and primary venation insculpate

above, margins entire in lower third, coarsely and remotely serrate in upper

two thirds, apices acute. Infl orescences terminal on fl owering shoots and well-

exceeding leafy portions, corymbose, 12 – 20 cm across x 8 – 12 cm tall, branch-

lets opposite, each subtended by a much-reduced leaf-like bract. Capitula

homogamous, discoid, pedicellate, pedicels 2 – 9 mm long, terete, moderately

to densely stipitate-glandular pubescent, usually 1 – 2-bracteolate, bracteoles

scale-like, linear, c. 3 mm long x 0.3 mm wide; involucre very narrowly-

campanulate to cylindrical; phyllaries subimbricate and effectively biseriate,

lightish green at base and pinkish-green above, outer phyllaries c. 3 mm long,

glandular-punctate throughout, margins laciniate, apices long-acute, inner

phyllaries 4 – 4.5 mm long, glandular punctate throughout, margins laciniate,

apices acute to obtuse, laciniate; receptacle small, ± fl at, glabrous. Florets

(6 – ) 7 – 12, hermaphrodite, scented (often quite sweetly so), producing good

quantities of nectar, corollas actinomorphic, 5-lobed, corolla lobes c. 1 mm

long x c. 0.8 mm wide, white, mamillose inside, often sparsely glandular-

punctate outside, apices acute to obtuse, corolla tube glabrous, white, 3.5 – 4

mm long x 0.4 mm diameter at base for c. 1.5 mm widening in upper part

to c. 1 mm; anther cylinder partially exserted, pinkish to pinkish-purple,

anther collar slightly thicker than fi lament and often very pale brown, fi la-

ments connected to corolla tube above narrower basal tube, glabrous, apical

anther appendage pinkish to whitish, broadly lanceolate, apices obtuse, basal

anther appendage shortly tailed, pinkish, entire, acute; style base glabrous

and somewhat swollen but not into distinct node, style shaft glabrous, style

arms c. 2.5 mm long, at fi rst erect, becoming ascending and fi nally spreading,

papillate in 2 lateral bands. Achenes 2.5 mm long, prismatic, body and ribs

concolorous, body blackish, sparsely glandular-punctate throughout and with

sparse twin-hairs on ribs, twin-hairs with unequal acute apices and scarcely

separated; carpopodium pale, cylindrical and appearing constricted above at

base of achene; pappus setae 2 – 3.5 mm long, barbellate, at fi rst a very subtle

pink turning pale brown with age, persistent and often somewhat fragile.

Fig. 1.

D ISTRIBUTION . Mexico, Guatemala, El Salvador, Costa Rica. However,

Mansfi eld (1945) and Genders (1978) gave the origin of the species, as E.

micranthum , as Chile, and Chile and Mexico, respectively. Baker (1869) sug-

gested ‘ A native of South America, the exact country not known. ’ and Anon

(1876) ‘ … a native of Brazil ’ for E. weinmannianum . All of them were clearly

in error!

H ABITAT . 900 – 2600 m. Montane cloud forest ( Turner 1997 ).

E TYMOLOGY . The specifi c epithet was clearly given by de Candolle because

of the plant ’ s leaves resembling those of Ligustrum spp.

F LOWERING T IME . Pruned plants may fl ower between August and November

or December, but the species can fl ower from March to May, July to September,

etc., and may well fl ower at least three times a year.

C YTOLOGY . n = 51 univalents ( Turner 1997 ).

U SES . Other than as a valuable horticultural plant, this species has no

documented uses, unless E. semialatum is included within its synonymy; this is

discussed further below.

V ERNACULAR N AMES . I NCENSE B USH , W EINMANN ’ S E UPATORIUM . One slightly

wayward internet site even referred to it just as ‘ Hemp Agrimony ’ simply

because it was listed under Eupatorium ; PRIVET-LEAVED HEMP AGRIMONY might

have been more appropriate.

D ISCUSSION . On a purely taxonomic point, it is worth comment-

ing upon the inclusion of E. semialatum in the synonymy of Ageratina

ligustrina , and the typifi cation of the former name. Bentham ’ s ac-

count of Hartweg ’ s collections (Bentham (1841) is sometimes mis-

interpreted by authors. Whilst his account is primarily based on

Hartweg ’ s collections, Bentham did include a number of other col-

lections in his account when he declared that they were the same

as Hartweg ’ s; this is especially true of Graham ’ s. The description

of Eupatorium semialatum is one such description which, although

based on Hartweg 532, actually cited an unnumbered Mexican Gra-

ham collection at the end of the protologue. Williams ’ comments

( Williams 1976 ) suggest that Hartweg 532 is the ‘ type ’ , although there

is no indication that he was aware of the Graham material. I do not

accept this as lectotypifi cation. The Hartweg 532 collection in K is

apparently from ‘ Sunil ’ ; the Graham collection (mounted with Hart-

weg 532 – ex Herb. Benthamianum) in K is numbered ‘ 32 ’ on the

sheet, since the collection has no label. I have selected Hartweg 523

specimen in K as the lectotype (see above).

© The Board of Trustees of the Royal Botanic Gardens, Kew 2006. 285

Fig. 1. Ageratina ligustrina . A, fl owering capitulum; B, l.s. capitulum; C, fl oret; D, corolla,

opened out showing attachment point of anther fi laments; E, anther; F, style base; G, style arm; H,

achene; J, detail showing twin hair from achene; L, detail showing apical portion of pappus seta.

Scale bars: A-H = 1 mm. Drawn by Margaret Tebbs from live material cultivated by the author in

Reading.

I have included E. semialatum with an element of doubt in the

synonymy of Ageratina ligustrina . Robinson (1926), King & Robinson

(1987) and Turner (1997) were of the opinion that E. semialatum

was a synonym of A. ligustrina . However, Williams (1976) expressed

some doubt, recognizing two separate species, and this is to some

degree supported by Lang (2001) and Lang et al. (2002) , following

detailed phytochemical work on sesquiterpene lactones extracted

from the leaves of both taxa. Lang et al. ’ s contention ( Lang et al.,

2002 ) was that antiplasmodially active sesquiterpene lactones (eudes-

manolides), present in E. semialatum have not yet been found in

A. ligustrina . In Central America leaves of the plant named as

E. semialatum have been used against malaria and dysentery, as well

as against other diseases and clearly the presence or absence of

these chemicals in the more widespread A. ligustrina is of some in-

terest. Apparent absence of chemicals in plant extracts is always

contentious and may simply indicate exceptionally low, or trace,

amounts. Whether this is enough to separate the two species will

need further, more detailed, morphological investigations.

REFERENCES

Anon . ( 1876 ). Eupatorium weinmannianum . Gardeners ’ Chronicle, n.s . 5 : 52 – 53 ,

& fi g. 12 .

Bailey , L . H . ( 1939 ). The standard cyclopedia of horticulture . Vol . 1 : A – E . The Mac-

millan Company , New York .

Baker , J . G . [& W.W. Saunders ] ( 1869 ). Tab. 155. E[upatorium]. Weinman-

nianum . Refugium botanicum 3: tab. 155 (tab. and accompanying text) .

Bean , W . J . ( 1973 ). Trees and shrubs hardy in the British Isles . Ed. 8 . ( Taylor , G . , Gen .

Ed .). Vol. 2 , D – M. Murray .

Bentham , G. ( 1839 – 57 ). Plantas hartwegianas imprimis mexicanas adjectis nonnullis

grahamianis enumerat novasque describit [auct.] London 1839 [-1857]. [alternative

title : Plantae hartwegianae … ] London [W. Pamplin] 1839 [-1857] .

Crane , T . J . ( 1879 ). Eupatorium Weinmannianum . Gardeners ’ Chronicle , n.s . 12 :

8xx – 8xx .

Dalyrymple , R . ( 1876 ). Eupatorium Weinmannianum (ligustrinum) . Gardeners ’

Chronicle , n.s . 5 : 340 .

Galloway , A . A . ( 2000 ). Eupatorium . In : Cullen , J . , Alexander , J . C . M . , Brickell ,

C . D . , Edmondson , J . R . , Green , P . S . , Heywood , V . H . , Jorgensen , P.-M. , Jury ,

S . L . , Knees , S . G . , Maxwell , H . S . , Miller , D . M . , Robson , N . K . B . , Walters ,

S . M . , & Yeo , P . F . ( eds ). ( 2000 ). The European Garden Flora, vol. VI Dicotyledons

(Part IV): Loganiaceae to Compositae . Royal Horticultural Society & Cam-

bridge University Press . [ pp . 663 – 666 ].

Genders , R . ( 1978 ). Scented fl ora of the world: an encyclopaedia . Granada Publishing

Limited , London, Toronto, Sydney New York .

Green , C . ( 1876 ). Eupatorium Weinmannianum . Gardeners ’ Chronicle , n.s . 5 :

115 .

Hillier , H . G . ( 1977 ). Hilliers ’ Manual of trees and shrubs . Ed. 4 . David & Charles,

Newton Abbot .

King , R . M . & H . Robinson ( 1987 ). The genera of the Eupatorieae (Astera-

ceae) . Monographs in Systematic Botany vol . 22 . Missouri Botanical Garden .

Körnicke , F . A . ( 1858 ). 11) Eupatorium Weinmannianum Rgl. et Kcke. und E.

Haageanum Rgl. et Kcke., zwei alte, aber unbeschriebene Pfl anzen unserer

Gärten . Gartenfl ora 7 : 52 – 54 .

Lang , G . ( 2001 ). Phytochemische Untersuchung der Blätter von Eupatorium semialatum

Benth., einer in Zentralamerika traditionell verwendeten Arzneipfl anze (“Bacché ” ) . PhD

Thesis , University of Düsseldorf .

Lang , G . , Passreiter , C . M . , Wright , C . W . , Filipowicz , N . H . , Addae-Kyereme , J . ,

Medinilla , B . E . & J.-J . Castillo . ( 2002 ). Antiplasmodial activities of sesquiterpene

lactones from Eupatorium semialatum . Zeitschrift Naturforschung, Tübingen. 57c :

282 – 286 .

Lord , T . ( ed .). ( 1990 ). RHS Plant fi nder 1990 – 1991 . Dorling Kindersley , London,

New York, Munich, Melbourne & Delhi .

Lord , T . ( ed .). ( 1996 ). RHS Plant fi nder 1996 – 1997 . Dorling Kindersley, London,

New York, Munich, Melbourne & Delhi .

Lord , T . , Armitage , J . , Cubey , J . , Lancaster , N . , & C . Whitehouse . ( 2006 ). RHS

Plant fi nder 2006 – 2007 . Dorling Kindersley, London, New York, Munich,

Melbourne & Delhi .

Mansfi eld , T . C . ( 1945 ). Shrubs in colour and cultivation . Collins , London .

Nees von Esenbeck , C . G . & S . Schauer ( 1847 ). Enumeratio et descriptiones

generum novorum specierumque plantarum in terris Mexicanis crescentium

quas Ruhlandus, Coloniensis, de Berghes et Dr. Aschenborn collegerunt .

Linnaea 19 : 681 – 734 .

Regel , E . ( 1867 ). I. Originalabhandlungen. 1). Abgebildete Pfl anzen. c) Eupa-

torium Weinmannianum Rgl. et Körn. Compositae . Gartenfl ora 16 : 260 & taf.

555, fi gs. 1 – 3 .

Robinson , B . L . ( 1904 ). 1. Diagnoses and synonymy of some Mexican and Cen-

tral American eupatoriums . In : No. 6. Contributions from the Gray Her-

barium of Harvard University. New series – No. 27 . Proceedings of the Boston

Society of Natural History 31 ( 6 ): 247 – 254 .

Robinson , B . L . ( 1926 ). Eupatorium . In : Standley P.C. , Trees and shrubs of

Mexico . Part 5 (Bignoniaceae – Asteraceae) . Contributions from the United States

National Herbarium 23 ( 5 ): 1432 – 1469 .

Royal Horticultural Society ( 1996 ). The Royal Horticultural Society A – Z encyclo-

pedia of garden plants . Vol. 1 A-J. [Revised edition 2003] . Dorling Kindersley

Limited , London .

Royal Horticultural Society ( 2004 ). Award of garden merit 2004, excluding fruit &

vegetables . Royal Horticultural Society , Wisley . [ www.rhs.org.uk ], et seq .

Sheat , W . G . ( 1948 ). Propagation of trees, shrubs and conifers . Macmillan & Co. Ltd ,

London .

Sheppard , J . ( 1875 ). Eupatorium Weinmannianum . Gardeners ’ Chronicle ,

n.s . 4 : 784 .

Standley , P . C . & J . A . Steyermark . ( 1944 ) .Compositae Studies of Central Amer-

ican plants – VI . Publications of the Field Columbian Museum of Natural History,

Botanical Series. Chicago 23 ( 4 ): 153 – 191 . [182 – 191] .

Sutton , J . ( 2001 ). The Plantfi nder ’ s guide to daisies . David & Charles , Newton

Abbot .

Thomas , G . S . ( 1992 ). Ornamental shrubs, climbers and bamboos . John Murray

(Publishers) Ltd. , London .

Thurston , E . ( 1930 ). British & foreign trees and shrubs in Cornwall . Cambridge

University Press , London .

Turner , B . L . ( 1997 ). Eupatorieae . In : Turner , B.L , The Comps of Mexico.

A systematic account of the family Asteraceae . Vol. 1 . Phytologia Memoirs 11 :

i – iv , 1 – 272 .

Vatke , ( 1872 ). Notulas de stirpibus quibusdam novis vel minus cognitas . Bota-

nische Zeitung 30 ( 40 ): 715 – 719 .

Voss , A . ( 1894 – 1896 ). Vilmorin ’ s Blumengärtnerei Beschreibung, Kultur und Verwendung

des gesamten Pfl anzenmaterials fur deutsche Gärten. Dritte, neubearbeitete Aufl age, unter

Mitwirkung von A. Siebert, … herausgegeben von A. Voss … Berlin (Verlagsbuchhand-

lung Paul Parey … ), 2 vols .

Westland , G . ( 1877 ). Winter-fl owering eupatoriums . The Florist and Pomologist .

26 – 29 .

Williams , L . O . ( 1976 ). Eupatorium . In Nash , D.L. & Williams , L.O ., Flora of

Guatemala . Fieldiana, Botany 24 ( 12 ): 46 – 104 .